To make a positive profit p(x)>0 we need to make:

Now we solve this for x:

We have:
a = -2
b = 7
c = -3
We will use formula for quadratic equation:

We got two solutions. One is fraction other is whole number. We will not consider fraction because the amount of muffins sold must be whole number. So our solution is:
x>3
Correlation coefficient (r) = [nΣxy - (Σx)(Σy)] / [sqrt(nΣx^2 - (Σx)^2)sqrt(nΣy^2 - (Σy)^2)]
Σx = 21 => (Σx)^2 = 21^2 = 441
Σy = 671 => (Σy)^2 = 671^2 = 450,241
Σx^2 = 1 + 4 + 9 + 16 + 25 + 36 = 91
Σy^2 = 98^2 + 101^2 + 109^2 + 117^2 + 119^2 + 127^2 = 75,665
Σxy = 1(98) + 2(101) + 3(109) + 4(117) + 5(119) + 6(127) = 2,452
r = [6(2,452) - 21(671)] / [sqrt(6(91) - 441)sqrt(6(75,665) - 450,241)] = 621/sqrt(105)sqrt(3749) = 0.99
option b is the correct answer.
Given : A florist currently makes a profit of $20 on each of her celebration bouquets and sells an average of 30 bouquets every week . and graph
To Find : Maximum profit , breakeven point , profit interval
Solution:
The maximum profit the florist will earn from selling celebration bouquets is $ 675
peak of y from Graph
The florist will break-even after Selling 20 one-dollar decreases.
at breakeven
Break even is the point where the profit p(x) becomes 0
The interval of the number of one-dollar decreases for which the florist makes a profit from celebration bouquets is (0 ,20).
after 20 , P(x) is - ve
Probability that gear 1 will fail = 5/100 (upto 10 years)
and 8/100 (after 10 years)
Probability that both will fail = 5/100 * 8/100
= 40/10000
= 0.4 %